Gear power unit



April 23, 1946- y J. K. MoRRls n 2,398,841

GEAR POWER UNIT JNVENToR. JH/v K Molen/5 April 23, 1946. 1 K MORR|S Y2,398,841

GEAR POWER UNIT Filed March 1, 1945 2 Sheets-Sheet 2 INVENToR. JH/vMone/5 Patented Apr. 23, 1946 UNITED srAras PA'raNr .oFFlca o 2,398,841X .nina me: cam.

This invention relates to a driving means and particularly pertains to agear power unit.

In the operation of various types of mechanism it is desirable toprovide a mechanical structure by which a rotating drive motion will betranslated into a lineal movement of a driven member, and between whichdrive and driven elements a suitable power increase will be obtained.Such structures are of particular value at' the presen-t time forremotely controlling parts of airplanes, as for example the controlflaps of the airplanes by which the wings are trimmed. In suchstructures an individual drive motor is provided, assembled with ahousing within which a train of rotary gears is mounted and throughwhich gears a reciprocating driven shaft is actuated, the motor circuitbeing controlled from the instrument panel of the airplane. In view ofthe fact.

often occurs that the driving motor will be operating at high speed whenthe reciprocating driven shaft has reached the end of its stroke, withthe result that the parts of the structure may be jammed or broken, f

It is the principal object of the present inven.. tion to provide a gearpower unit of compact and sturdy design embodying a driving motor, adriving gear set, and a reciprocating driven shaft, the structureincluding snubbing means to absorb the impact shock when thereciprocating element reaches the end of its stroke, and further actingto dissipate torque shock incident to the operation.

'I'he present invention contemplates the provision of a housingincluding-a train of rotary reduction gears operating a rotating shaftand a reciprocating element carrying a shackle yconnection at its outerend and by which a desired lineal motion may be imparted by movement ofthe reciprocating element.

The invention is illustrated by way of example in the accompanyingdrawings in which:

Figure 1 is a view in central longitudinal sec-V tion through the gearpower unit with which the the outer end of the operating connectionthrough the reciprocating member.`

Fig. 4 is a fragmentary view in longitudinal section showing a modiiiedform ing anti-friction bearings.

Referring more particularly to the drawings. III indicates a drivingmotor. This motor is here shown as being an electric motor and it is ofcourse controlled by a suitable electric circuit and electric switch.The switch is disposed at a point remote from the unit with which thepresent invention is concerned. It is understood that any other type ofprime motor might be used if desired. The motor is mounted upon abolting flange II and is secured in place by screws I2.

The bolting ange is part of a gear case I3. This gear case has a forwardwall I4 formed with an opening I5 through it in axial alignment with themotor I0. The drive shaft I3 of the motor extends through this openingand carries a driving pinion I1. 'I'his pinion is a worm which is inmesh with a worm wheel I8. 'I'heworm wheel I8 is mounted upon a shaft I9which is disposed at an angle to horizontal, and thus makes it possiblefor the gear case I3 to be of unusually small dimensions whileaccommodating various gears to be hereinafter described. The shaft I9 ismounted at its uppermost end in a bearing 2li and at its lowermost endin a bearing structure 2|. The bearing structure 2| is directlyVincluded within a cap 22 secured within a bore 23 of the housing I3 bycap screws 24. Mounted upon the shaft I9 or formed integral therewith isa worm present invention is concerned, and discloses the reciprocatingdriven member and the drive thereshaft I6 and the motor III and extendsforwardly of the motor. For convenience in description only, it is to beunderstood that the motor In is disposed horizontally, and that theentire unit functions with the motor III and the shaft 21 lying inparallel horizontal planes. It is understood, however, that the unit maybe disposed in any required position in actual operation.

- 'I'he shaft 21'has`a reduced portion 28 which terminates in a threadedend 29, and a suitable anti-friction bearing 30 is mounted on thereduced portionj 28 and iscarried within'a cage 3|. The cage' 3I`lsmountedwithin a bearing portion 32 of acover plate 33, which issecured to the gear case I3 by'cap screws 34 and is disposed of butlerlncludps1-enel to the mnt piste u er the geslease. The worm gear 25 ismounted upon the reduced portion ofthe driven shaft 21 and is keyed withrelation thereto. A nut $5 engages the threaded end 25 of the shaft andsupports the shaft with relation to the bearing 25.

Secured over the end of the bearing portion 32 of the cover plate Il isa cap 55. This is formed with a lug 21 fto receive pivot pin. 25 bywhich a. suitable connectingmember (notV shown) is atasoasei of theshaft 21. Similar contiguous flat faces 5I areformeduponthediscs..Thesediscsare preferably made of steel. and the contiguous faces 55 and5l are ground smooth. A film of grease is disposed between thecontiguous faces 55 and 55 to facilitate in relative rotation of thediscs 55 v and 55. A nut 4l is threaded onto the outer end tached to thegear case and either supports the case or provides an operatingconnection therewith.

`The-forward face' I4 of the gear case Il is formed with a tubularbearing portion 55 through of the portion 52 of the shaft 21 and holdsthe members 54, 55 and' 55 in assembled relation to each other upon theshaft. l Attent ion is directed to the fact that the diameters of thediscs 55 and 55 are larger than the diameter of the threaded which theshaft 21 extends. vAnti-friction bearings 45 are mounted within thistubular portion and support the shaft. The position of these bearings isslightly in advance ofthe reduced portion 25 ofthe shaft.

- Extending outwardly from the front face of portion 44 of the shaft 21,and that they are also larger than the outside dimensions of the nut 55.The innermost disc 55 thus presents an inner face 5l to end face'52 ofthe nut 5I which is \assemblecl with the thrust sleeve 45. The outer thewa11i4 of the gear case i! is aboss 4i. Se-

' driven shaft 21 and prevents leakage of the grease or other lubricantwith which the gear case i5 is packed. Reciprocably mounted within thetubular housing and around the portion 44 face 53 of the outer disc 55may be encountered by a stop face 54 formed asa part of the yoke 41, asshownin Fig. 1 of the drawings. It is t0 be understood that theconnection between the yoke 41 and the member operated by the yoke,

and which is attached by a pin 55, holds the yoke of the driven shaft 21is a thrust sleeve 45. This sleeve has a sliding iit in relation to thebore of the tubular housing 43. The outer end of the thrust sleevereceives a yoke 41 which is held in place by cap screws 45.' 'I'his yokeis formed with a. transverse bore 49 to receive a suitable connectingpin by which the yoke is attached to a device to be actuated, suchforexample as a wing flap (not shown in the drawings).

'I'he outer end of the tubular housing is formed I with a packing gland50 which circumscribes the thrust sleeve 45 and forms a iiuid sealtherewith. The inner end of the thurst sleeve is formed with a tubularnut 5I which is secured 'to the sleeve by any suitable means, such aswelding. This nut has a central threaded bore engaging threads on thesection 44 of the driven shaft 21. Thus, as

the shaft. 21 is rotated the nut will move therealong and willsimultaneously reciprocate the thrust sleeve 45. It will be evident thatas the shaft 21 rotates to move the thrust sleeve 45 to the extreme endof its stroke in either direction, the shaft 21 may possibly continue torotate and exert a longitudinal movement upon the thrust sleeve 45,since the circuit vof the motor I0 may still be closed. In order toresistthis movement a snubber structure is provided, as generallyindicated at 52. This structure .is mounted upon a reduced end portion53 of the section 44 of the driven shaft 21 and includes a deformablewasher 54 disposed between setsof washers 55 and 55.

The deformable element 54 is preferably made of some synthetic rubber,such as neoprene 'I'he washers 55, directly contacting the oppositesides ofthe neoprene vdisc or ring, are preferably formed of brass orbronze.' The opposing faces of the washers 55 are concave, as indicatedat 51, and the diameter of the washers 55 is greater than the diameterof the neoprene disc 54, for a purpose to be hereinafter described. -Theouter faces of the discs 5.5,"as Aindicated at 55, are

at and in planes normal to the longitudinal axis and the thrust sleeveagainst rotation. This likewise acts to hold the nut 5i againstrotation, so that rotation of the driven shaft 21 will impartlongitudinal movement to the nut 5| and the thrust sleeve 45.

When it is desired to use the device as here shown, the .parts are builtand assembled as described in the foregoing specincation. Attention isdirected particularly to Fig. 2 of the drawings, where it-will be seenthat since the shaft I5 is disposed obliquely to the vertical planeoccupied by the shafts i5 and 21 and is not disposed in a positionnormal to this plane, the shafts vlli and 21 may be placed relativelyclose together, and the size of the gear case I3 may be reduced to aminimum, both as to dimensions and weight. After the structure has beenassembled as shown, the motor I5 may be operated.

This will impart rotation to the drive shaft I5 and the worm i1, whichin turn will rotate the worm gear I8 in the direction of the arrow a, asshown in Fig. l. The worm 25 will then be driven and will impartrotation to the worm` wheel 25 in the direction of the arrow b, as shownin Fig. 2. As this takes place the threaded engagement of the portion 44of the shaft 21 with the nut 5|- will cause the thrust sleeve 48 to moveoutwardly in the direction of the arrow c, as shown in Fig. 1, and willproject it from the end of the .tubular housing 43. This action willcontinue until the end face or shoulder 52 of the nut 5I will encounterthe face 5| of the steel washer 55. The

lcf the washer 55. Incident to this action the washers and 55 will tendto rotate with relation to each other, thus dissipating the torque forceof the driven shaft 21, and will also tend' to deform the disc 54 whichis positioned between the washers 55. In view of the fact that the disc54 bears against concave faces 51 of the discs 55, there will be atendency for the outer circumference of the disc 54 to be confinedbetween the washers while causing'the material of the memill having adriving speed of 3500 revolutions per minute, and that the thrust andtorque forces exerted between the shoulder 82 andthe washer 58 isconsiderable. The structure here disclosed damps this force and preventsinjury to the parts. When the driven shaft 21 rotates in acounterdirection to that indicated by the arrow b in Fig. 2, the thrustsleeve 48 will move in a counterdirection to the arrow c in Fig. 1.'I'his will continue until the shoulder 64 on the yoke 41 abuts againstthe outer face 63 of the outermost disc B. The same snubbing action willthen be obtained as previously described.

Referring to Fig. 4 of the drawings. it will be seen that anti-frictionbearings 55' are interposed between the discs 55 and 56.

It will thus be seen that by the structure here disclosed it is possibleto provide a gear power unit within which rotary motion is convertedinto lineal motion by a compact, light weight, eililcient gear set, andwhich structure insures that at opposite ends of the stroke of thethrust sleeve the force will be damped and the driven shaft brought torest without damage to the parts of the unit. l

While I have shown the preferred form of my invention as now known tome, it will be understood that various changes may be made incombination, construction and arrangement of parts by those skilled inthe art, without departing from the spirit of my invention as claimed.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. In combination, a rotatable member and a member moving longitudinallythereof to describe a. reciprocating stroke of iixed length, stopshoulders carried by the member moving longitudinally and being disposedadjacent to the opposite ends thereof to denne said stroke length; abuffer structure mounted upon said rotatable member and rotatablerelative thereto, said structure including a deformable disc interposedbetween a pair of rigid discs being adapted to alternately engage thestops on the longitudinally movable member at the opposite ends of thestroke of said longitudinally movable member.

2. In combination, a rotatable member and a member moving longitudinallythereof to describe a reciprocating stroke of fixed length, stopshoulders carried by the member moving longitudinally and being disposedadjacent to the opposite ends thereof to define said stroke length; abuier structure carried by the rotatable member and being free to rotatearound the axis thereof, said buffer structure including a pair of rigiddiscs freely rotatable upon said rotatable member and having limitedlongitudinal movement on their mounting, and a yieldable andcompressible disc mounted upon the rotatable member and interposedbetween said frst named discs in face contactywhereby said yieldabledisc may be compressed and will frlctionally resist relative rotationbetween the rigid and yieldable discs as one of these stops on thelongitudinally movable member encounters one of the relatively rigiddiscs to bring the longitudinally movable member and the rotatablemember to rest.

3. In a device of the character described, the combination of'arotatable screw shaft, a tubular member mounted thereon for longitudinalreciprocation, said tubular member being held against. rotation, a nutthreaded onto the shaft and fixed to the tubular member, wherebyrotation of the shaft in opposite directions will produce alternate ffree to rotate with relation to the extension and to move longitudinallythereof, shoulders on the threaded shaft limiting longitudinal movementof the discs. a deformable buffer disc normally filling the spacebetween said rst named discs, and spaced shoulders on the longitudinallymovable member between which the buffer is positioned and adapted toalternately encounter one of said pair of discs at each end of thestroke of said tubular member to frictionally engage the same and totend to compress the buffer disc and seil up friction between the facesof the discs while bringing both the longitudinal member and therotatable member to rest.

JOHN K. MORRIS.

